Endocrine Abstracts

Introduction: Thyroid autoimmunity has been associated with the diagnosis of differentiated thyroid (DTC) cancer in surgical series. However, this finding has not been consistent in Fine Needle Aspiration Biopsy (FNAB) cytology series.

Aim: We aimed to investigate the association between thyroid autoimmunity and DTC in patients who underwent ultrasound-guided FNAB.

Methods: A retrospective analysis of patients who had undergone ultrasound-guided FNAB between Jan 2014 and Nov 2015 was performed. Patients were classified into two groups, according to the presence of thyroid auto-antibodies (ATA): ATA negative (ATA −) and ATA positive (ATA+) patients. In ATA+ patients, either one or both antibody types (anti-thyroid peroxidase abs or anti-thyroglobulin abs) were positive. Patient demographic characteristics, the presence of risk factors for thyroid cancer and nodule size were recorded. Cytology reports were classified, according to the Royal College of Pathologists guidance, as negative for malignancy (Thy2), possible neoplasm (Thy3), suspicious for malignancy (Thy4) and malignant (Thy5). Non-diagnostic cytology reports (Thy1) were excluded. The frequency of possible neoplasm, suspicious or malignant (Thy3, Thy4, Thy5) was estimated in the two patient groups (ATA−, ATA+).

Results: During the study period 673 nodules of 466 patients were biopsied. Thyroid autoimmunity was present in 41.8% of patients. The frequency of suspicious or malignant (Thy3, Thy4, Thy5) cytology reports was comparable in the two patient groups (5.8% in ATA+ patients vs. 4% in ATA− patients; P=0.303).

Conclusion: In the present study, no association between the presence of thyroid autoimmunity and suspicious or malignant findings in thyroid nodule cytology was found.